grep: extend functionality, add man page entry, add unit test.
walkchangerevs now returns a two-tuple. Its behaviour is also
extensively commented.
The annotate command's getname function has been factored out to a new
function, trimname, so it can be shared between annotate and grep.
The behaviour of grep has been beefed up, so that it now performs a
number of useful functions.
#!/bin/sh
mkdir test
cd test
echo foo>foo
hg init
hg addremove
hg commit -m 1
hg verify
hg serve -p 20059 > /dev/null &
sleep 1 # wait for server to be started
cd ..
hg clone http://localhost:20059/ copy
cd copy
hg verify
hg co
cat foo
hg manifest
hg pull
kill $!